One of the biggest contributors to successful buildings is the design and placement of windows, including glazed doors and skylights.
While this is measurably and undoubtedly true, the topic of windows is often only a secondary consideration to architects, builders, and building owners…mistakenly taken up after, rather than concurrently with, the planning of walls, roofs, and their structural underpinnings.
We’d like to spend a few minutes discussing some window essentials, to inspire and help you to make superior design and building choices in this crucial area.
Window Elegance Without Efficiency & Efficiency Without Elegance
The American architect Frank Lloyd Wright was a leader in the integrated use of windows in modern building design. Influenced by traditional Japanese design practices, as his Rosenbaum House above suggests, Wright recommended that window design and placement be part of our overall thinking about a building’s shape and fabric, and the ambient space that floors, walls, and ceilings naturally combine to create.
Wright in particular abhorred design thinking that led to the conceptual cutting of holes in preordained and immovable walls for windows and doors. Instead, he encouraged seeing these building elements in a more holistic way, where permeable and solid materials flowed harmoniously from one to another in designed patterns, each element possessing an intrinsic beauty while contributing to a larger design scheme.
Wright’s often famous buildings are of course admired by many for their aesthetic sensibility and natural elegance. Unfortunately, this broad admiration of his work does not extend to the efficiency and practicality of his designs – which were often expensive to build and maintain – reminding us that pragmatic and cost considerations are an essential part of any truly holistic building and design process.
Important Window Design Criteria
Regardless of where you live, there is likely easily accessed governmental and trade information on window design standards and selection criteria. Three examples are Window Efficiency, Energy Performance Ratings, and Energy Efficient Windows. If this is new territory for you, we would encourage you to spend a few minutes reviewing these fairly valuable summary materials.
Wright’s Masterpiece: Showing How Windows Can Be Integral To Design
As you can see, these and similar information sources make quick work of key practical considerations in window design and selection – including quality measures and cost efficiency, commonly available styles, optimizing heat gain & loss, and use and installation information.
However, these same sources typically offer only incidental guidance on aesthetics and the integrated use of windows in the design process. It’s a big gap, at once reflecting and perpetuating our modern bias toward buildings designed with poor attention to and a limited aesthetic sense of how windows can and should be used in building design – a sense well-evidenced in the recently acclaimed but dark and glaring BedZED project above .
To address these important aesthetic shortcomings, and to summarize and augment common practical guidance on window design and selection, we’d like to offer several window design ideas for you to consider:
> Placement for efficiency – often well-covered in standard window information materials, efficiency practices include maximizing winter heat gain and minimizing it in summer, use of insulated glass, considering building placement, care with window placement, and the use of optimal overhangs and sources of shade. These are all important criteria of course, since windows and glazing are often a building’s largest single source of favorable and unfavorable heat transmission.
> Placement for aesthetics & livability – this topic is normally and unfortunately reserved for architectural programs and similar venues, and even there is subject to poor or limited attention. For this reason, although the aesthetic placement of windows is at least as important as efficiency considerations, it remains greatly unappreciated or misunderstood, especially in modern building design. But this needn’t be the case, since general and quite simple principles of design apply to the use of windows to create more interesting and lively spaces. These include a) clustering windows, b) using windows to create pleasing patterns, c) framing windows in ways that create added interest and appeal, and d) coloring windows and frames to harmonize or contrast with other building elements. As suggested, all of these steps involve a more integrated and perhaps imaginative sense of the place and placement of windows in building design.
> Proportion – the amount of window area needed for a building can be thought of usefully in terms of percentage of floor area. A ten percent ratio is quite common and is often mandated by building codes. Ratios less than this can be more energy-efficient but often produce dark and dispirited interior spaces (and may necessitate mechanical air exchangers and added electric lighting). By contrast, higher window-to-floor area ratios create a higher amount of light, but have cost and energy efficiency trade-offs, and can even lead to less comfortable living conditions via greater variability in background radiant heat levels.
> Distance – interior spaces more than three meters (ten feet) from a window are apt to be increasingly dark, unless skylighting is used, suggesting placement of utility areas or intentional contrast zones where lower light is acceptable or desirable.
> Layering – normally triple glazing (and quadruple in cold climates) is most efficient and the best value for long-term building owners (or when measured from a societal standpoint), since the added cost for extra layers of glass is low and energy performance returns are high compared with the baseline or fixed costs of single glazed windows – owing to the fact the principal costs of most windows are their millwork, transportation, and installation, not the glass itself.
> Multi-directional light – it has been understood by architects for centuries that having windows on more than one wall in a room can produce superior lighting and more aesthetically pleasing interior spaces. While this practice can increase costs and is not always possible due to site conditions or design considerations, a simple way to achieve this result is to intentionally move rooms away from sharing common wall lines – creating a stepped effect where rooms have secondary walls at least partially exposed to the outside. In keeping with our earlier discussion about holistic design, this and alternative practices compel designers to think iteratively about building layout, the number and location of available walls, and potential window placements and patterns.
> Views – windows are often placed in response to existing views with high appeal. Alternatively, landscaping is sometimes done to improve the view from existing windows. While both approaches have merit, it is worth considering the nature of views in general, and especially as they occur over time. The truth is that we naturally habituate to views, however compelling, and the importance of a prized view is often over-emphasized in our immediate preferences and the intuitive design practices that can follow from them. Often, superior practical and aesthetic window use, and higher long-term building satisfaction, can be achieved by partially occluding a dominating view or by creating multiple or unfolding perspectives on a view via selective and attentive window use.
We hope this brief introduction to window design will spur new questioning and ideas in you, whether for a current or future project. Windows are an essential but often overlooked and under-appreciated aspect of building design – from both practical and aesthetic standpoints – and frequently are a ready means to greatly improve building quality and to expand and enrich our building practices.
As always, we invite your comments on innovative building practices and our opportunities to promote more functional, natural, and beautiful modern buildings.
Mark Lundegren is the founder of ArchaNatura.
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